Features Smoke alarm detector 433 smoke alarm detector can be used with Sonoff RF bridge 433 to realize APP alarm after smoke fire Through the scene alarm can be set to link other eWelink switches Note not include battery battery model 9V 6F22 Weight 128gPacking size 11 10 4cm1 3 seconds alarm sensitive response using infrared scattering principle fire smoke alarm for about 3 seconds timely alarm reduce your property loss to controllable range 2 Sound and light alarm when the smoke reaches the predetermined value the indicator light flashes quickly and emits a green light prompt and the smoke alarm alarm sounds about 110 decibels 3 360 degree smoke detection alarm no dead angle reliable 4 Built in 110 decibel sound and light alarm prompt effective prompt evacuation site built in high sensitivity sensing technology reliable safe 5 Suitable for a variety of scenarios independent type does not require an external power supply suitable for families hotels office buildings factories etc Package included 1 x 433MHz Smoke alarm detector1 x User manual2 x Screw caps2 x Fixing Screws